1. Field of the Invention
The present invention relates to a method for designing a structure and particularly to a method for generating a model at an initial designing stage.
2. Description of the Related Art
Various methods for designing a structure have been proposed. For example, Japanese Patent Laid-Open Publication No. Hei 3-224063 discloses an optimal designing system in which an interface is provided between an analytical calculation section and modeling section; changes of design parameters for a structure and remodeling are automatically performed based on the analytical result; and an optimal model which, satisfies the design specification, is output after design iteration.
In this method, modification of the model makes the design specification satisfied after each iteration. However, this reference does not describe any technique for generating the basic original shape or configuration. Current structural design depends on a designer's experience or on his design notes, and no tool exists for generating the original shape (analysis model). Certainly, it is possible to re-design a configuration using the above method or a design support program, such as the AISI/CARS program for automobile structure member design once the original shape is generated.
Finite element analysis (FEA) based on detailed mesh models is widely used in the analysis phase. However, much calculation time and a large number of design changes are required to regenerate a model after each design change in the case where the original model is unreasonable. This is because the convergence and calculation time is determined from the completeness of the original model.